Many current design interfaces for building webpages are either flow-based or absolute-positioning Flow-based design interfaces place objects at relative locations during webpage design while absolute-positioning design interfaces place objects at absolute locations during webpage design. Thus, when an object is moved in a flow-based interface, the flow-based interface will place the selected object relative to other objects in the interface rather than at an absolute location in the interface. The flow-based interface places the object above or below or right or left relative to existing objects and moves existing objects to accommodate the moved object. Many designers, however, consider flow-based design interfaces irritating and ineffective because these interfaces do not permit designers to move objects wherever they wish and maintain positions of other, unmoved objects. A designer may wish to move an object to a particular absolute location but with flow-based design is not permitted to do so. Rather than be permitted to place the object at a desired location the interface instead places it relative to objects in the interface.
In contrast, absolute-positioning design interfaces permit designers to move an object wherever the designer chooses. Absolute-positioning interfaces, however, estimate, during design, what a final webpage will look like. These estimates are often wrong and require additional processing to create publishable HTML code, which results in an unsatisfactory design experience for many designers.